In a high speed wrapping and packaging machine such as a horizontal wrapping machine, a continuous film of packaging material is supplied from a roll and drawn past a film former which shapes the film into a continuous tube of packaging material. Products to be wrapped are supplied through the film former and into the tube of packaging material such that products are spaced apart from one another in the packaging material tube. The packaging material tube is then cut and sealed as each product, carried within the tube, passes a sealing and cutting station. As the products advance through the sealing and cutting station, a pair of opposed cut/seal heads are rotated into engagement with the packaging film tube at a location on the film tube between each successive pair of products. The cut/seal heads typically carry a cutting blade along with heated crimpers on one cutting head shaft extending transversely to the packaging film tube and an anvil along with heated crimpers on the other cutting head shaft which cooperates with the cutting blade and crimpers for performing the cutting and sealing operation thereby forming discrete packages.
A variety of product sizes can be packaged with a single wrapper by changing the type of cutting head shaft arrangement found at the cutting and sealing station. A cutting head is typically configured with one, two or four crimpers. The cutting head shaft can also vary in diameter. It is very time consuming to change the cutting heads on a wrapper. Three to five hours are often spent changing the head configuration on conventional wrappers. Thus, a cutting head arrangement that allows for a quick change-over of the wrapper cutting head configuration is desirable.
Wrappers additionally have problems that arise when product becomes misoriented as it is packaged. The wrapping machine is designed to obtain the proper orientation of each product relative to a cut length of film, the cut length being the amount of film used in each package. The cutting blade and anvil should come together at the proper point between the products in the film tube. Any shifting of the product position relative to the packaging film will result in a misorientation condition. A product may lose its necessary orientation as it is introduced into the packaging film tube and sealing station and a product may also lose proper orientation if any slippage occurs within the packaging film tube. When a product falls out of registration with the synchronized operation of the cutting and sealing heads the cutting blade and anvil come together with the product sandwiched therebetween. The product is destroyed and furthermore, the packaging film material is lifted and pulled out from between the finwheels used to create the longitudinal seal in the wrapper.
Premature failure of the two cutting heads also results when the cutting heads attempt to cut through both product and packaging film material. Furthermore, the packaging machine must be shut down to clear the damaged product and to reroute the packaging film material through the film former and between the finwheels. This detracts from the production rate for the machine, is time consuming and disruptive to the high speed packaging production runs.
To address the problem of misoriented products, a prior art cutting head assembly was developed in which the upper cutting head was mounted to deflect away from the cutting area instead of attempting to cut and seal the misoriented product. Thus, if the cutting blade and anvil contacted a misoriented product in the packaging film material instead of just the packaging film material, the upper cutting shaft is deflected away from the cutting area instead of attempting to cut and seal the product. As a result, the cutting heads did not experience the premature failure of the non-deflecting prior art cutting head arrangements. However, this prior art cutting head arrangement does not resolve the problem of the packaging film material being pulled out of line in the finwheels and film former. In this prior art arrangement, the product and film must ride up over the non-deflecting cutting shaft surface causing the packaging film material to be pulled out of line in the finwheels and film former. Again, such an event requires the shut down of the packaging machine while the fault condition is cleared, thus detracting from the production rate for the machine. Additionally, this prior art cutting head arrangement still requires several hours of machine down time to replace the cutting head configuration.
The present invention provides a solution that addresses the need for a quick head configuration change-over, the problem of premature failure of the cutting heads and the problem of the packaging film material being pulled out of line in the finwheels and film former. A modular cut/seal shaft arrangement is used. Each cut/seal head shaft end is journaled in a bearing block. The bearing blocks slide in channels comprising the cut/seal head frame assembly, thus allowing the cut/seal heads to be quickly removed and replaced with a different head configuration. Additionally, both cut/seal shafts are mounted so that when products become misaligned and are caught between the cutting blade and anvil, both cut/seal head shafts are deflected away from the cutting area. The cutting blade and anvil do not attempt to cut through the product and the packaging film material is not pulled out of the finwheels. Wrapping and packaging production can continue without shutting down the packaging machine for clearing the cutting area of the damaged product and packaging film material and for rerouting the packaging film through the finwheels.
The use of two driven shafts in which each driven shaft incorporates two u-joints enables the deflection of the shafts away from the cutting area. Furthermore, the use of the u-joint driven shafts spreads the torsional forces throughout the cutting head assembly.
It is accordingly a principal object of the present invention to provide an improved apparatus and method for a cut/seal head apparatus used in a high speed packaging machine.
A further object of the present invention is to provide a modular cut/seal shaft arrangement that provides a quick change over to a different cutting head configuration, allowing quick set-up when different products to be packaged are run on the wrapper.
Another object of the present invention is to provide a modular cut/seal head apparatus which allows the user to quickly select and position the modular cut/seal head shafts in the cut/seal head frame at the desired operating position.
A still further object of the invention is to provide a cutting head apparatus which responds to a misaligned product without causing the packaging film material to become dislodged from the finwheels or the film former, thus minimizing the loss of packaging film material.
Still another object of the present invention is to provide a cutting head apparatus which responds to a misaligned product without causing premature wear and failure of the cutting head apparatus.
Yet another object of the present invention is to provide a cutting head apparatus which responds to misaligned products without causing the product to become damaged from the cutting operation of the cutting head apparatus.
A still further object of the present invention is to provide a cutting head apparatus which incorporates two cutting heads shafts that will deflect away from the product in the cutting area when the two opposed rotating cutting shafts contact a misaligned product therebetween, thereby preserving the product integrity, preventing packaging film material from becoming dislodged or pulled from the finwheels and film former and preventing waste of the packaging film material.